1. Field of the Invention
The present invention relates to an end-face heating apparatus, a method for drying an end face of a honeycomb aggregated body, and a method for manufacturing a honeycomb structured body.
2. Discussion of the Background
In recent years, particulates such as soot and the like contained in exhaust gases discharged from internal combustion engines of vehicles, such as buses and trucks, and construction machines, have raised serious problems as those particulates are harmful to the environment and the human body.
There have been proposed various ceramic filters using a honeycomb structured body comprised of porous ceramics, which serve as filters capable of capturing particulates in exhaust gases to purify the exhaust gases.
FIG. 1 is a perspective view that schematically shows one example of such ceramic filters; FIG. 2A is a perspective view that schematically shows a honeycomb fired body that constitutes the ceramic filter; and FIG. 2B is a cross-sectional view taken along line A-A of FIG. 2A.
In a ceramic filter 130, a plurality of honeycomb fired bodies 140 as shown in FIGS. 2A and 2B are combined with one another by interposing sealing material layers (adhesive layers) 131 to form a ceramic block 133, and a sealing material layer (coat layer) 132 is formed on the periphery of this ceramic block 133.
Moreover, as shown in FIGS. 2A and 2B, the honeycomb fired body 140 has a structure in which a plurality of cells 141 are placed in parallel with one another in the longitudinal direction and a cell wall 143 between the cells 141 is allowed to function as a filter.
In other words, as shown in FIG. 2B, each of the cells 141, formed in the honeycomb fired body 140, is sealed by an opening-sealing material layer 142 at either one end of its exhaust gas-inlet or exhaust gas-outlet sides so that exhaust gases that flow into one of cells 141 are discharged from another cell 141 after surely passing through a cell wall 143 between cells 141, and accordingly, when exhaust gases pass through the cell wall 143, particulates are captured by the cell wall 143 portion so that the exhaust gases are purified.
Conventionally, in order to manufacture a ceramic filter 130 of this type, first, for example, ceramic powder, a binder, a dispersant solution and the like are mixed to prepare a wet mixture. This mixture is then continuously extrusion-molded through a die, and the extruded molded body is cut into a predetermined length to manufacture a rectangular pillar-shaped honeycomb molded body.
Then, the resulting honeycomb molded body is dried and after predetermined cells are sealed to make the cells under a state in which one of the end portions is sealed by the opening-sealing material layer, the result is subjected to degreasing and firing processes to manufacture a honeycomb fired body.
Thereafter, plural honeycomb fired bodies are integrated with one another by interposing a sealing material paste layer therebetween, to manufacture a honeycomb aggregated body. Then, the respective end faces of this honeycomb aggregated body is heated, the sealing material paste layer close to the end face is dried, and the entire sealing material paste layer is dried thereafter to form a sealing material layer (adhesive layer) on the honeycomb aggregated body.
Next, the resulting honeycomb aggregated body with the sealing material layer (adhesive layer) formed thereon is cut into a predetermined shape such as a cylindrical shape, a cylindroid shape or the like by using a cutting machine and the like to form a ceramic block, and lastly, a sealing material paste is applied to the periphery of the ceramic block to form a sealing material layer (coat layer), thereby completing the manufacturing process of a ceramic filter.
Normally, the ceramic filter thus manufactured is used in a state of being housed in a casing.
In the present specification, among the surfaces which form the outer contour of any of the honeycomb molded body, honeycomb fired body, honeycomb aggregated body, ceramic filter and honeycomb structured body, the surface of which the cells are exposed are referred to as an “end face” and the surface other than the end face is referred to as a “side face”.
With respect to the method for heating the end face of the honeycomb aggregated body, and drying the sealing material paste layer on a proximate portion of the end face, in the method for manufacturing the ceramic filter as mentioned above, JP-A 2004-291270 discloses, for example, a method for jointing a ceramic structured body in which a plurality of ceramic structured bodies of which side faces are put in a state where a jointing material is interposed therebetween are applied with pressure in the direction to which the ceramic structured bodies come close to one another, to remove the jointing material which has been extruded from the end face of a integrated body of the plural ceramic structured bodies, the jointing material remaining near the end faces of the integrated body can be dried thereafter.
The contents of JP-A 2004-291270 are incorporated herein by reference in their entirety.